Hitherto, a device described in Patent Literature 1 is provided, for example, as a device for collecting sound around a housing. The device in Patent Literature 1 includes microphones on respective surfaces of a tetrahedron, so that the device can collect sounds in all directions.
There is also proposed a device in which sound-collection directions of three unidirectional microphones are displaced 120 degrees apart outwardly and the sound in all directions are collected so as to detect the direction of the sound source on the basis of a sound-collection level of each unidirectional microphone (see Patent Literature 2, for instance).
A device for collecting sound in an arbitrary direction using a plurality of microphones is also proposed (see Patent Literature 3, for instance).